The other placebo study included 20 knees in the treatment group and 18 knees in the placebo-treatment group. The third study provided a comparison between patients treated with three weekly injections of Hyalgan® followed by 2 weekly treatments with arthrocentesis with patients treated with arthrocentesis for five weeks, and arthrocentesis and placebo injections for five weeks. Additional arms of this study assessed additional treatment regimens. Statistical evaluation of the data was performed at day 60. In this study, only patients considered to be success were followed beyond day 60. These patients were followed for 180 days, however, due to the number of dropouts, statistical evaluation was not performed on data gathered at time points beyond day 60. The results of these investigations reported that the three-injection Hyalgan® treated patients experienced pain relief beginning at day 21 and continuing throughout the remaining 60-day observation period.